Racial disparities in dementia are due to social determinants of health, with genetic ancestry playing no role, according to a new study led by researchers at Washington University School of Medicine in St. Louis.
The study, which was based on a long-running population-based survey in four Latin American countries, helps explain why people of predominantly Native American or African ancestry have a higher prevalence of dementia: Study participants were more likely to experience social contexts and health conditions that raised their risk of cognitive decline, such as lower education levels, rural residency and high blood pressure. Once such factors were accounted for, ancestry added no additional risk.
“Marginalized racial and ethnic groups have higher rates of dementia in many countries, and disentangling the biological from the social contributors has been challenging,” said corresponding author Jorge Llibre-Guerra, MD, an assistant professor of neurology. “Latin America provides a unique framework to separate the two. It is the region with the largest mixture of genetic ancestries, plus it has profound social inequalities. This study clearly shows that poor cognitive health is part of the legacy of the racial caste system. It’s not family ancestry that is putting people at risk. In a way, the findings are reassuring, because social determinants of health are modifiable.”
The study is available online in the journal Alzheimer’s & Dementia.